Pushbutton combination locks are known. Such a pushbutton combination lock is for example disclosed in GB-A-2 176 233. The lock disclosed in GB-A-2 176 233 comprises a series of pushbuttons on both sides of the lock so that from both sides the number combination can be entered to unlock the lock. From neither side of the door, the door can be freely opened so that the door or gate does not have to be completely closed to prevent access to the door handle on the other side of the door or gate. This is especially the case for outdoor doors or gates, such as garden gates or gates in fences. Although the lock comprises a series of pushbuttons on both sides, it comprises only one series of tumbler members and only one check slide. The pushbuttons on both sides of the lock act therefore onto the same tumbler members so that a same number combination has to be used on both sides of the lock. It is thus not possible to set one complex number combination on the outer side and a less complex combination on the inner side.
Another known pushbutton combination lock is disclosed in EP-B-1 984 591 of the applicant of this application. In this pushbutton combination lock two locking mechanisms are provided such that a first code can be chosen for the first side and a second code for the second side.
A disadvantage of both above described pushbutton combination locks is that a code has to be entered on both sides of the gate to be able to open the gate. EP-B-1 984 591 discloses in one of the embodiments of this patent a solution for this problem. The keyboard is on one side of the lock replaced by a keyboard with only one large pushbutton so that the lock can very easily be unlocked from one side of the door or gate. This solution still has the problem that the lock first has to be unlocked before the door or gate can be opened. Further, such a mechanism is expensive because a second locking mechanism is required. In some constructions, it's also possible to push the large pushbutton by a long bar or rod from the other side.